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Self-Propelled Robot Pinpoints Leaks in Pipes

Researchers at MIT have developed robots small enough to monitor pipes from the inside (Source: MIT)

Researchers at MIT have devised a novel method of pinpointing leaks in underground pipes, using a robotic system that can speedily detect leaks by monitoring high-risk changes in pipe pressure.

Gas explosions have plagued major cities for years, collapsing buildings and endangering the lives of many. Additionally, gas leaks can contribute to global warming conditions, by producing methane – a greenhouse gas that outstrips CO2 in terms of harm –wasting large amounts of water, and even more dangerously, causing toxic oil spills that not only take a great deal of manpower and money to clean up, but also pose a serious threat to humans and the environment.

Thus far, pipes have been monitored using acoustic sensors that listen for faint sounds or vibrations that can signal pipe breakages, or using in-pipe detectors that sometimes use cameras to monitor the state of pipes below-ground. However, while metal pipes vibrate enough for acoustic sensors to record, plastic pipes dissipate sound too quickly, and cannot be properly monitored using the same technology. Because of this, existing pipe monitoring systems are ultimately too slow to recognize many pipe breakages, and have proved insufficient to addressing the risk that explosions can pose.

To address this serious problem, scientists at MIT and Saudi Arabia’s King Fahd University of Petroleum and Minerals (KFUPM), supported by MIT’s Center for Clean Water and Energy, have developed a new monitoring system that can identify pipe leaks in record time, using small robots to locate extreme changes in pipe pressures.

The system consists of two parts: tiny robots, only a few inches wide, that can move through pipes, on wheels or on liquid currents, at high speeds of up to 3 mph, paired with a tight membrane sealed across the width of the pipes. When leaks occur, liquid pulls the membrane towards the leak site, creating a distortion that can be registered by sensors in a mechanical system operating through the roving robot, which reports the information wirelessly so that the leak can be addressed.

The new technology “can detect leaks of just 1 to 2 millimeters in size, and at relatively low pressure,” Dimitrios Chatzigeorgiou, lead author of the research papers and a Ph.D. student in mechanical engineering at MIT, said in a recent press release.

This new robotic technology is especially important for the degree of accuracy with which it can address the exact location of leaks, using GPS technology. According to Chatzigeorgiou, “Detecting leaks by sensing a pressure gradient close to leak openings is a novel idea…and key to the effectiveness of this method: This approach can sense a rapid change in pressure close to the leak itself, providing pinpoint accuracy in locating leaks.”

Because of this extreme sensitivity of the membrane and the efficiency of the robots, scientists on the team believe that their system can detect leaks of one-tenth and even one-twentieth the size that current acoustic technology is capable of registering.

Additionally, unlike previous acoustic monitoring systems, the robots are almost entirely self-automated, and unlike previous sytems, require no expert operators. Theoretically, they could provide 24/7 pipe monitoring of large systems at a rapid pace, and at an attractively reduced price; previous monitoring systems could cost $250,000 annually to monitor 100 km of pipe.

“We’re hoping this system will be much more affordable,” co-author Rached Ben-Mansour, a professor of mechanical engineering at KFUPM, said.

The new system “is very important because of its size,” Arnold Scott, vice chairman and director of First Commons Bank, who mentored the team in the MIT $100K Entrepreneurship Competition, said. “It is the only [inspection device] small enough to fit inside of a 4-inch pipe. Many modern water systems are built using 4-inch pipe, so being able to inspect this pipe diameter is very important. Another important element is the reporting mechanism. Using GPS, this [device] can specifically locate and report the location of a leak in a pipe.”

The researchers are currently working on a more flexible version of their system, which can work with pipes of different sizes, as well as those affected by damage, scale build-up, or other obstacles. They are also working on increasing the speed of their robots to ensure even faster monitoring. Additionally, the team has conferred with gas and water companies to negotiate testing their concept in the real world, confident that their technology could successfully detect leakages in industrial gas, oil, or water pipes.